This invention relates to films of LLDPE having excellent anti-blocking properties. More specifically, this invention relates to films of LLDPE made from blends of LLDPE and vulcanized ethylene-propylene elastomers, and to such blends themselves.
Linear low density polyethylene (LLDPE) is a polymer whose commercial production is now well established. Linear ethylene polymers such as LLDPE are widely used in the extrusion of films because of their superior properties compared to high pressure polyethylene. One drawback of LLDPE films, however, is that they tend to block or adhere together in a nonpermanent but relatively strong bond after the films have been in face-to-face contact under pressure for some time. Rolls of the film may be difficult to unwind if the take-up tension has been great enough to cause a significant amount of blocking to take place, and surface imperfections may be created as the roll is unwound. Although the phenomenon of blocking may be put to use in certain laminate products, it would be desirable to have some means of reducing the blocking tendencies of the films.
There are known additives for improving the antiblocking properties of films which are commercially available. They may be chosen from a wide variety of materials including inorganic compounds such as silica and silicates. It is well known that the use of inorganic antiblocking agents can adversely affect the physical properties of thin films. Accordingly, there is a need for a LLDPE film with excellent anti-blocking characteristics which avoids the disadvantages attendant to prior art films containing anti-block additives.